It is known to construct a roller bearing assembly of several independent parts, usually in the shape of rings. These parts are mounted together and secured relative to each other by means of welding so as to form an extremely rigid assembly that is relatively inexpensive to manufacture and at the same time unlikely to come apart as a result of vibration. In the fabrication of roller bearings, four different race surfaces are usually defined between the inner and outer races, with the outer race usually formed of two welded-together race members, one having two race surfaces and the other having a single race surface.
The principal disadvantage of such welded-together assemblies is that the very process of welding the parts together creates internal stresses in these parts which can distort the race surfaces. Obviously once the assembly is welded together it is impossible further to machine it so that either these distortions of the race surfaces must be accepted, or the assembly must be scrapped. Thus welded-together rolling rearings are generally inferior to those bearings which are not fabricated by welding.
It has been suggested to interconnect the various parts by just a few spot welds so to reduce the creation of internal stresses as much as possible. This is partially effective but produces relatively weak assemblies. In another known arrangement the various parts are made as massive as possible so as to minimize the effects of the local heating due to the welding operation. Such construction increases the bulk and cost of the assembly. Neither of these methods is fully effective, since even very small thermal stresses can distort the race surfaces and thereby make the bearing unacceptable.